Sources

A news article (hard or soft) should have at least three sources,
and should mention each source at least once in the first half of the
story. (Don't leave "the opposing view" until the last paragraph.)

A movie or restaurant review might not have any interviews at all --
the whole article would be based on the reporter's direct observations.

A news story might include quotes from

an official who makes an announcement

a member of the public reacting to the announcement, and

somebody whose reactions differs from the previous source

Depending on the nature of the story, a reporter might include balanced quotes from people on opposite sides of an issue, and a
third person who is an expert in the subject matter but not involved in
this particular dispute. (So, for instance, if you cover a dispute
between a landlord and a tenant, you might interview the author of a
book about similar cases.)

Note: For a news article, three sources is a minimum.
For
a routine story, professional reporters might interview a dozen people,
but only quote five or six in the story. (The other interviews are to
double-check what the main sources say.) Investigative reporters
might have scores of contacts.